Elastic fluid power plant



June 1940. P. H. KNOWLTON, JR 2,204,139

' ELASTIC FLUID POWER rum Filed Dec. 3, 1938 Inventor: aul H. KhowlconJn,

hi? Act orn ey.

45 skilledin-theart- 1 56 from the auxiliary turbine is conducted through mama June 11, 1940 PATENT orrlcs nmsnc nun) POWER rum rm n. Kim'lhll, In, Schenectady, N. 1., as-

signer to General Electric poration of New York Company, a cor- I Application December 8, 1988, Serial No. 244,. I 'Ciaims. (Cl. 60-70) The present invention relates to elastic fluid power plants in which elastic fluid such as steam or mercury vapor is produced in an elastic fluid generator and supplied-to consuming apparatus.

5 The elastic fluid generator usually comprises a boiler in which liquid is heated and evaporated, a furnace for heating the boiler and means for sup-- plying and controlling the supply of combustlbles to the furnace. The consuming apparatus may comprise an elastic fluid turbine, meansfor conducting and regulating the flow of elasticfluid to the turbine and means including a condenser for receiving the exhaust fluid from the turbine. The means for supplying and regulating the supply of feed fluid to the boiler and the means for supplying oombustibles to the furnace may include pumps and a blower driven by an auxiliary elastic fluid turbine receiving operating fluid from the boiler.

- My present invention is an improvement over the invention of the G. B. Warren application, Serial No. 244,624, flied December 8, 1938,- and assigned to the General Electric Company, which invention was made by the said G. B. Warren prior to my invention. I therefore do not herein claim anything shown or described in said Warren application, which is to be regarded as prior art with respect to this present application;

The object of the present invention is to provide an improved arrangement for power plants of the type specified whereby the control and regulation of the various apparatus is accomplished in a simple manner.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended theretotaken in connection with the accompanying drawing.

A power plant system embodying my invention is shown in the drawing in a diagrammatic form only, omitting, for the sake of clarity, such supplemental apparatus as pilot valves. valve actuating motors, and other incidental control auxiliaries which may be supplied as desired by one In the drawing. ll' indicates an elastic fluid generator comprising ammo and a boiler of the pumped through-type which supplies elastic fluid through a conduit H to the consuming apparatus. Elastic fluid from the conduit Ii. is admitted through a suitable control valve II, preferably of the sectional admission type, to an auxiliary turbine i8 provided'for driving the elastic fluid generator a The exhaust fluid a conduit It to a main turbine ll through a suitable admission controlling valve Ii. The main turbine I! may be utilized for driving any suitable load, not shown, connected to the'shaft ll extending therefrom. The exhaust fluid from 5 the main turbine may be received by suitable condensing apparatus llindicated in this instance asbeing of the surface cooled type. The condensate from the condenser may be conducted by means of a connection It to a storage reservoir .or hot-well 2| from whence it may be returned by means of conduit II, booster pump 22, conduit II; boiler feed pump 24, and conduit 25 to the boiler of the elastic fluid generator Ill. The booster pump 22 is illustrated as being of the 15 centrifugal type and may be driven by any suitable motor, not shown. 'The boiler feed pump 24, preferably of the positive displacement type, is shown diagrammatically as comprising 9. cylinder 2' having a reciprocating piston 2! arranged therein provided with a stem III, the end of which is adapted to be engaged by a cam means 2| driven by the shaft 3! of the auxiliary turbine It. The piston may be biased to an upper position by a spring means ll. Fluid flow through 25 the pump is controlled by means of check valves 32 and SI suitably arranged in the inlet and outlet 'ports respectively of the pump. It is obvious that any suitable type of boiler feed pump may be used for applying suitable pressure to the liquid 30 to be forced into the boiler and inadditlon, it is understood that while I illustrated the pump 2| as being driven directly from the shaft 30, it may be desirable to provide a suitable speed reduction gearing in the driving connection.

The auxiliary turbine, in addition to driving the boiler feed liquid pump, is also arranged for driving additional boiler auxiliaries, such as the combustion air blower l4 and the furnace fuel pump 35. For the sake of clarity, as withv the boiler feed liquid pump 2|, the combustion air blower and the fuel pump are shown as being directly driven by the auxiliary turbine shaft 30 although it is understood that suitable speed re- --duction gearing may be used in the driving con- 45 nections to these devices as desired. The combustion air blower is arranged for drawing air through an inlet It and discharging it through a conduit 81 to the furnace of the elastic fluid furnace burner.

The valves i2 and It (controlling the admission 'of elastic fluid into the auxiliary and main turas bines respectively are connected together for simultaneous movement and are adapted to be adjusted in accordance with the condition of load on the main turbine. The sectional admission valve controlling the flow of elastic fluid to the auxiliary turbine I3 is biased to the closed position by spring means I2. This valve is adapted to be operated to the open position by downward movement of a link 4|, the lower end of which is pivotally connected to one end of a fulcrumed lever 42, the other end of the lever 42 being connected as by link 43 to the end of the stem 44 extending from the valve It.

A suitable form of speed governing mechanism may be employed for adjusting the elastic fluid admission valves so as to maintain a substantially constant speed of the main turbine l5 under varying conditions of load. As shown, a speed governor 45, adapted to be driven through gearing 46 from the extension 41 of the main turbine shaft, is arranged for controlling the position of the valves l2 and i6 through a suitable hydraulic operating mechanism including a pilot valve 48 and a servo-motor 49. As shown, the pilot valve 48 comprises a cylinder 50 having valve heads 5| and 52 slidably arranged therein, the valve heads being mounted in a spaced apart relationship upon a stem'53, the end of which stem is connected for movement by the speed governor 45. The servo-motor 49 comprises a cylinder 54 having a piston 55 slidably arranged therein. The chambers in the cylinder 54 above and below the piston 55 communicate with the pilot valve through connections 56 and 51 respectively. Operating fluid for the servo-motor, such as oil under pressure, is adapted to be supplied to the pilot valve through connection 58 and is drained therefrom through connections 59 and 50. A stem 8i secured to the piston 55 of the servo-motor 49 is connected, as at 62, to an end of a lever 93 which in turn is pivoted intermediate its ends to a. stationary part 64. The other end of the lever 53 is connected as by a link 85 to an arm 66 secured to the valve stem 44.

Except as modified by the supplemental control apparatus to be described later, the major changes in the output of the various auxiliaries to the elastic fluid generator are automatically made in accordance with the demand for elastic fluid of the main turbine. By the proper adjustment of the interconnection between the admission valves l2 and It, the speed of the auxiliary turbine may be caused to vary in accordance with the supply or elastic fluid to the main turbine and since the boiler auxiliaries, that is, the boiler feed liquid pump, the combustion air blower and the fuel pump, are arranged to be driven through connections from the auxiliary turbine shaft, the output of these units will vary substantially in proportion to the speed thereof. Assume, first, that the power plant is operating in equilibrium with normal conditions obtaining, that is, with the main turbine operating with a constant load and the elastic fluid generator auxiliaries driven at such a speed as to cause the proper amount of elastic fluid to be generated as is required for the particular load. Now assume that the load on the main turbine for some reason increases causing it to decrease slightly in speed. The flyweights of the governor will drop a certain amount moving the pilot valve heads upwardly establishing communication between the supply of operating fluid and the upper chamber of the servo-motor 49 whereupon the piston thereof will be forced downwardly. This movement of the servo-motor to the main turbine valve 66. This movement will also be imparted through the link 43 to the fulcrumed lever 42 rotating it in a clockwise direction to move the auxiliary turbine valve l2 simultaneously to a more opened position. Normally, due to the proper adjustment of the movable pivot about which the lever 42 is fulcrumed, the valve I6 will be moved to a relatively wider opened position than the valve l2 so that the back pressure to the auxiliary turbine l3 will be relatively lower with respect to the admission pressure thereto in the new position of adjustment than in the previous position. Thus the pressure drop through the auxiliary turbine is slightly greater in the new position of the valves than previous to the change whereby the speed thereof is proportionately increased to cause an increased output of the auxiliaries which increased output will be substantially in proportion to the increased demand for elastic fluid of the main turbine. Conversely, upon a decrease in load on the main turbine, the speed of the auxiliary turbine will be decreased by a reverse operation of the control mechanism described above to decrease the output of the boiler auxiliaries.

Since the speed of the auxiliary turbine is determined by the pressure drop experienced by the elastic fluid in passing therethrough, supplemental means are provided for controlling such pressure drop by adjusting the connection between the valves l2 and it so that the relative ratio of the opening and closing movement of these valves with respect to each other is varied as required by conditions obtaining with respect to the elastic fluid generator. This is accomplished, according to the invention, by the provision of means responsive to the flow of elastic fluid in the main supply conduit and also to the level of liquid in the boiler. As indicated in the drawing, the lever 42 connecting the valve operating members 4i and 46 is pivoted intermediate its ends at 6? to an adjustable support 58. The lever 42 is provided with a longitudinal slot 69 in which the pivot pin is adapted to slide as the support is moved. The support 68 is mounted for sliding engagement upon a suitable base in. The lengths of the valve operating connections are so adjusted with respect to the lever 92 that when the valves are in their wide opened position, the lever M will lie in a position substantially parallel with the base it. With the valves in some mid position, the lever #32 will assume some angular position with respect to the base such as that indicated. The pivot support is adapted to be adjusted in response to variations in pressure drop across a variable orifice or valve II in the boiler feed liquid conduit 23. A differential pressure responsive device 12 is connected across the valve ll, which comprises a casing 13 having a flexible diaphragm l4 therein forming chambers on opposite sides thereof with the casing. The chamber on the right is in communication by conduit 15 with the conduit 23 ahead of the valve 7 l, as regards the direction of flow therethrough, while the left chamber is in communication by conduit 16 with the conduit 23 behind the valve II. A biasing spring TI is suitably arranged between the left side of the diaphragm and the casing for determining the operating characteristics of the device. The flexible diaphragm is connected 'as by a stem 18 to pilot valve heads 19 and 80 slidably arranged within the pilot valve cylinder 8|. The operating motor for the adjustable pivot of the piston 88. Operating fluid is drained from the pilot valve through either of the connections 88 or 89.

The biasing spring of the pressure responsive device I2 has such characteristics that the diaphragm assumes a central position upon a predetermlned pressure drop obtaining acrossthe valve 'II regardless of the degree of opening of, said valve. The valve 'II is adapted to be adjusted in accordance with the elastic fluid flow through the main supply conduit II and also in accordance with the quantity of liquid in the boiler. This control system includes a flow responsive device 90 and a liquid level responsive device 8| differentially connected together.- As shown, the elastic fluid flow responsive device "comprises a casing 92 having a flexible diaphragm 88 therein forming chambers on either sides thereof with the casing. The chamber on the left is in communication by a connection 84 with the elastic fluid conduit II ahead of a nozzle 98 provided therein. The chamber .on the right is in communication as by connection 96 with the elastic fluid conduit II behind the nozzle, as regards the direction of flow therethrough. A biasing spring 91 is arranged between the right side of the diaphragm and the, casing for determining the operating characteristics of the device. The liquid level responsive device 9| comprises a casing 98 having a flexible diaphragm 99 therein forming chambers on either side thereof with the casing. The quantity of liquid in the boiler is measured as by a suitable float m'eans I arranged in a drum IOI thereof. An indication of the level of the liquid therein is transmitted from the float through a link I02 to a lever I08 pivoted to a stationary part I04. Fluid fllled collapsible bellows devices I and I88 are arranged on opposite sides of the lever I08 for transmitting the liquid level indication to the device 9I', the bellows I05, above the lever I08, being in communication as by conduit I01 with the chamber on the right, while the bellows I08 is in communication as by conduit I08 with the chamber on the left of the device 9|. The stems I09 and H0 connected to the diaphragms 93 and 99 of the devices 90 and 9|, respectively, are connected together as by a floating lever III which in turn is pivotally connected at an intermediate point I I2 to a lever II8 which in turn is pivoted at one end to a stationary part H4. The other end of the lever H8 is pivotally connected as by a link Hi to an operating lever N8 of the valve II.

The mode of operation of this regulating apparatus is as follows: assume, as before, that the system is operating in equilibrium with normal conditions obtaining and that for some reason the load on the main turbine has increased causing the admission valves I2 and I6 to be actuated to a more opened position in accordance with the increased demand. The increased flow of elastic fluid through the mainsupply conduit II will to the right. If the water level in the drum I0l remains normal the device 9| will be inactive whereupon the lever III will be rotated in a clockwise direction causing the pivotal connection II2 with thelever II8 to be moved to the right and through the arm II5 cause the valve II to be moved to a more opened position. Assumlng that upon the change of position of the admission valves, I2 and I8, the auxiliary turbine I8 has not increased in its speed in proportion to the increased elastic fluid flow through the supply conduit II and that as a consequence the output of the feed liquid pump 24 has not increased in proportion to the opening movement of the valve II whereupon the pressure drop thereacross has decreased below the predetermined value, the pressure on the left side of the diaphragm of the device I2 will thereupon increase causing it and the pilot valve heads connected thereto to be moved to the right. Upon this movement operating fluid will be supplied to the servo-motor associated therewith to move the piston 88 thereof and the movable pivot support 68 connected thereto to the left. The pivot pin 61 will be moved in the slot 89 of the lever 42 causing the lever 42 to pivot about its left end in a counterclockwise direction moving the admission valve I2 to a slightly more closed position.

This movement of the valve I2 will result in a decrease of supply of elastic fluid available for the main turbine l6 whereupon through the governor mechanism associated therewith the valve l8 will be moved to a further opened posi tion. As the valve I6 is further opened, the pressure in the conduit I4 will decrease resulting in a greater pressure drop through the auxiliary turbine I8 causing it to increase in speed and accordingly increase the speed or output of the boiler feed liquid pump 24. The speed of the auxiliary turbine I8 will in this manner be increased until the pressure drop across the valve II assumes the predetermined constant value upon the occurrence of which condition the diaphragm I4 of the device I2 will assume its central position moving the pilot valve heads associated therewith to the neutral position arrestingthe movement of the servo-motor associated therewith and the movable pivot support 68. The auxiliary turbine will thus be regulated for the proper speed and the system will be stabilized for the new condition of load.

Conversely, if the readjustment of the admis sion valves I2 and I6 upon an increased load on the main turbine results in an excessive increase of speed of the auxiliary turbine causing the output 01' the boiler feed liquid pump 24 to increase disproportionately as regards the new position of the valve 1|, the pressure drop thereacross will be greater than the predetermined constant value. Accordingly, the pressure in the chamber on the left of the diaphragm 14 of the device I2 will drop causing the diaphragm, and the pilot valve heads I9 and 80 connected thereto to be moved to the left. The piston of the servomotor associated therewith will be moved to the right causing the movable pivot support 88 to be moved therewith rotating the lever 42 in a clockwise direction and actuate the admission valve I2 .to a more opened position. Upon the resultant increase of elastic fluid flow therethrough, the valve I8 will be moved to a somewhat more closed position upon the consequential over-' speeding of the main turbine I5. Accordingly, the back pressure to the auxiliary turbine I8 will be increased reducing the pressure drop thereacross to somewhat decrease the speed thereof and consequently the speed and output of the boiler feed liquid pump 24. This manner of regulation will be continued until the pressure drop across the valve H is re-established at its predetermined constant value whereupon the diaphragm 14 of the device 12 will reassume its normal neutral position and the system stabilized as before.

It will be noted that the valve H is also con nected for adjustment in accordance with the level of the liquid obtaining in the boiler drum IOI. Assume that the level of the liquid therein should fall below a predetermined position causing the link I02 to move downwardly rotating the lever I03 in a clockwise direction. Due to the accompanying compression of the bellows device I05 and the expansion of the bellows device I05,

the auxiliary turbine I3 and, accordingly, the

speed and the output of the boiler feed liquid pump 24 to re-establish the predetermined level of liquid in the boiler drum. Upon such reestablishement the predetermined level, or upon a level higher than the predetermined position obtaining in the boiler drum, the reverse operation of the apparatus will take place to move the valve 1! to a more closed position to slightly decrease the speed of the auxiliary turbine and the supply of feed liquid to the boiler. By the interconnection of the devices 90 and 9I through the floating lever III, as shown, the valve 1| in the boiler feed liquid conduit 23 will be adjusted in accordance with the differential indication of the two devices.

The supply of combustibles to the furnace of the elastic fluid generator is further regulated in accordance with the variations of the pressure of elastic fluid in the main supply conduit II. As indicated in the drawing this is accomplished by means including a pressure responsive device comprising a cylinder II1 having a piston H8 arranged therein, the left end of which cylinder is in communication with the supply conduit II by a conduit II9 extending from the conduit 95. A stem I secured to the piston H8 is pivotally connected to an arm I2I arranged for operating a damper I22 in the combustion air conduit 31. The piston H8 is biased against the elastic fluid pressure by means of a spring I23 substantially as shown. The proper ratio between the air passed by the damper I22 to the furnace and the fuel supplied to the furnace is regulated by means including flow responsive devices I24 and I25. The device I24 comprises a casing I26 having a flexible diaphragm I21 arranged therein forming chambers on opposite sides thereof with the casing. The chamber on the left of the diaphragm is in communication by conduit I28 with the air supply conduit 31 ahead of a nozzle I29 provided therein. The chamber on the right of the diaphragm is in communication by conduit I30 with the air supply conduit 31 behind the nozzle I29 as regards the direction of air flow therethrough. Similar to the device I24, the device I25 comprises a casing I 3| having a'ilexible diaphragm I32 arranged therein forming chambers on the opposite sides thereof with the casing. The chamber on the right is in communication by conduit I33 with the fuel supply conduit 40 ahead of a nozzle I34 provided therein. The chamber on the left is in communication by conduit I35 with the fuel supply conduit behind the nozzle I34 as regards the direction of fuel flow therethrough. The stems I35 and I31 secured to the diaphragm I21 and I32 of the devices I24 and I25, respectively, are connected together by means of a floating lever I38. The floating lever is pivotally connected intermediate its ends as at I33 to one end of a lever I40 which is pivoted at the other end to a stationary part I. Movement of the lever I40 is imparted by a connection link I42 to the valve I43 arranged in the fuel supply conduit .40 between the fuel pump 35 and the nozzle I34. In the event that the output of the fuel pump 35 is in excess of that allowed to pass the valve I43 provision is made by means of conduit I44 for by-passing the excessfuelfrom the conduit 40 back to the fuel storage tank 39. A pressure relief valve I45 is arranged in the bypass conduit which may be adjusted to open upon a predetermined pressure obtaining in the conduit 40 between the fuel pump 35 and the valve I43.

In the operation of'the last described apparatus, as the pressure in the elastic fluid sup ply conduit II is decreased, the damper valve I22 in the combustion air conduit 31 is moved to a more opened position whereupon the supply of combustion air to the furnace is increased. As the flow of air to the furnace is increased,the proper ratio between the air and fuel is maintained by thecooperation of the flow measuring devices I24 and I25.

As the flow of air through the nozzle I29 in the air supply conduit 31 increases, the pressure in the chamber to the left of the diaphragm I21 of the device I24 will increase causing the stem I35 secured thereto to be moved to the right. Accordingly, the lever I38 will be rotated about its lower end moving the pivotal connection I39 with the lever I40 to the right which in turn will operate the valve I43 in the fuel supply line 40 to a more opened position. As the fuel flow through the nozzle I34 is increased, the pressureon the right side of the diaphragm I32 of the device I25 will be increased whereupon the stem I31 connected thereto will move to the left carrying with it the lower end of the floating lever I30 effecting a throttling action of the valve I43.

Conversely, upon the rise in pressure of elastic fluid in the supply conduit II, the damper I22 in the combustion air conduit will be throttled to a more closed position which in turn will cause a proportionate decrease in the supply of fuel to the furnace burner.

From the foregoing desoriptionit will be seen that the entire power plant system is substantially automatically regulated in response to changes in load on the main turbine. During normal operation, the adjustment of the inter-' connecttion between the auxiliary and main turbine admission valves which results in the proper speed changes of the auxiliary turbine for the different loads of the main turbine becomes substantially fixed. It is understood that during normal load variations the level of liquid in the boiler drum will remain substantially constant since the liquid supplied thereto by the boiler feed pump is adiusted'in accordance with the variations of flow of elastic fluid from the boiler.

Upon the occurrence of abnormal conditions, the liquid level in the boiler drum may vary one way or the other whereupon the output of the feed liquid pump will be adjusted independently of the load on the main turbine to reestablish the predetermined level. During all load conditions the supply of combustibles to the furnace is automatically regulated as to maintain a substantially constant predetermined boiler pressure.

Having described the method of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a power plant, the combination of an elastic fluid generator comprising a furnace, a boiler, a fuel pump, a combustion air blower and a boiler feed pump, an auxiliary turbine for driving said pumps and said blower, a conduit for conducting elastic fluid from said boiler to said auxiliary turbine, a main turbine, a conduit for conducting elastic fluid from said auxiliary turbine to said main turbine, admission valves for controlling the supply of elastic fluid to each of said turbines, means for adjusting said valves in accordance wtih the load on said main turbine, and means for supplementally adjusting the admission valve of said auxiliary turbine in accordance with a condition of operation of said elastic fluid generator.

2. In a power plant, the combination of an elastic fluid generator comprising a furnace, a boiler, a fuel pump, a combustion air blower, and a boiler feed pump, an auxiliary turbine for driving said pumps and said blower, means for conducting elastic fluid from said boiler to saidauxiliary turbine, a valve for controlling the admission of elastic fluid to said auxiliary turbine, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine, a valve for controlling the admission of elastic fluid to said main turbine, means for adjusting said main turbine admission valve in accordance with the load on said main turbine, means connecting said auxiliary turbine admission valve for operation with said main turbine admission valve, means for adjusting the relative movement of said auxiliary turbine admission valve with respect to movements of said main turbine admission valve for varying the regulation of said auxiliary turbine.

3. The combination of an elastic fluid generator comprising a boiler, and a furnace, a main turbine, a conduit for conducting elastic fluid from said generator to said turbine, a valve for controlling the admission of elastic fluid to said turbine, means for regulating said admission valve in response to a load condition of said main turbine, a boiler feed pump, a fuel pump, a furnace draft blower, an auxiliary turbine arranged in said elastic fluid conduit ahead of said main turbine for driving said pumps and blower in accordance with the elastic fluid demand by said main turbine, an admission valve for said auxiliary turbine, an interconnection between said auxiliary turbine admission valve and said main turbine admission valve regulating means, and means for adjusting said interconnection whereby said auxiiiary turbine admission valve may be supplementally regulated relative to said main turbine admission valve in response to a condition of operation of said elastic fluid generator. 4. In a power plant, the combination of an elastic fluid generator comprising a furnace, a

. fluid from said boiler to saidauxiliary turbine,

valve means for controlling the admission of elastic fluid to said auxiliary turbine, a main turbine adapted to receive elastic fluid from said auxiliary turbine, valve means controlling the admission of elastic fluid to said main turbine, means for adjusting said main turbine admission valve means, means connecting said auxiliary turbine admission valve means for actuation with said main turbine admission valve means, means for regulating the relative movement of said auxiliary turbine admission valve means with respect to movements of said main turbine admission valve means in response to variations in elastic fluid flow from said boiler and in response to variations in the liquid level in said boiler.

5. In a power plant, the combination of an elastic fluid generator comprising a boiler, a boiler feed pump, an auxiliary turbine for driving said pump, a conduit for conducting elastic fluid from said boiler to said auxiliary turbine, a valve for controlling the admission of elastic fluid to said auxiliary turbine, a main turbine, a conduit for conducting elastic fluid from said auxiliary turbine to said main turbine, a valve for controlling the admission of elastic fluid to said main turbine, actuating means responsive to a load condition of said main turbine for simultaneously adjusting said admission valves, a

conduit for conducting boiler feed liquid to said boiler feed pump, a variable orifice in said last mentioned conduit, said oriflce being adjustable in response to elastic fluid flow from said boiler and means responsive to variations in pressure drop across said variable oriflce for adjusting the relative movement of said auxiliary turbine admission valve by said actuating means with respect to movement of said main turbine admission valve.

6. In a power plant, the combination of an elastic fluid generator, a liquid feed pump, an auxiliary turbine for driving said pump, a conduit for conducting elastic fluid from said -generator to said auxiliary turbine, an admission valve for said auxiliary turbine, a main turbine connected for receiving elastic fluid from said auxiliary turbine, an admission valve for said main. turbine, means interconnecting said main turbine and auxiliary turbine admission valves, means for simultaneously adjusting both of said admission valves in accordance with a load condition of said main turbine, and means for adjusting said interconnection in, response to a differential indication of the flow of elastic fluid from said generator and of the liquid level in said generator.

7. In a power plant, the combination of a boiler, boiler feeding auxiliaries, an auxiliary turbine for driving said auxiliaries, conduit means for conducting elastic fluid from said boiler to said auxiliary turbine, a main turbine adapted to be driven by the exhaust fluid from said auxiliary turbine, admission valves for each of said turbines, a governor driven by saidmain turbine,

adjustable means connecting said admission valves for simultaneous adtuation'by said governor, and means including said adjustable connecting means for supplementally adjusting said auxiliary turbine admission valve in response to a condition of operation of said boiler.

8. The combination oi a first elastic fluid turbine, conduit means for conducting elastic fluid to said turbine, a valve for controlling the admission of elastic fluid to said turbine, a second turbine,conduit means for conducting the elastic fluid exhaust from said first turbine to said second turbine, a valve for controlling the admission of elastic fluid to said second turbine, means including a lever mounted on a pivotal support interconnecting said first and second turbine admission valves, governor means for adjusting said valves in accordance with a load condition of one of said turbines, and means for adjusting the pivotal support with respect to said lever for varying the relative adjustment between said admission valves upon actuation 0! said governor sion valve for said turbine, a second turbine adapted to be driven by the exhaust fluid from said first turbine, an admission valve for controlling the flow of fluid to said second turbine, means for simultaneously adjusting the admission valves of said first and second turbines in accordance with a condition of load on said second turbine, and means automatically operable in response to a condition of operation of said boiler for varying'the relative amount of adjustment of said first turbine admission valve with respect to a predetermined adjustment of said second turbine admission valve.

PAUL H. KNOWLTON, Jn. 

